Leland Yee, who showed up John Avalos’ campaign kickoff, is sharing the SEIU endorsement with him.

It didn’t take long today for state Sen. Leland Yee’s camp to declare his co-endorsement in the mayor’s race from the city’s largest public employee union was “a complete rejection of the city’s top official, interim Mayor Ed Lee.”

But a closer look at the endorsements by the Service Employees International Union suggests that at least one big winner is the pension reform measure that Lee has championed with Supervisor Sean Elsbernd and other elected officials.

SEIU local 1021, which represents more than half of all city workers, had been on the fence about the measure. But along with endorsing Yee and Supervisor John Avalos as co-first and second choices for mayor (that’s the beauty of ranked-choice voting, you don’t have to pick just one), SEIU also endorsed the “city family” measure, which is backed by other public employee unions.

The Chronicle

John Avalos was an organizer and political coordinator for SEIU.

That had to be a bit disappointing for Public Defender and last-minute mayoral candidate Jeff Adachi, whose competing pension measure specifically goes easier on the lowest-paid city employees — many represented by SEIU — than on those making more.

“As you can imagine, it’s not exciting to vote to take away from yourself, but for obvious reasons our members understand we’re in a challenging economy and some things needed to be fixed,” said Gabriel Haaland, the union’s political coordinator. “They looked at them side by side and rejected Adachi’s measure and supported the consensus measure.”

Former Supervisor Bevan Dufty got SEIU’s nod for third choice in the mayor’s race.

Lee’s campaign spokesman, Tony Winnicker, shrugged off the lack of an endorsement from a union that has historically been aggressive in trying to stave off cuts to the city workforce during tough economic times.

“Mayor Lee had to make tough choices to balance the budget, and some members of SEIU’s leadership are unhappy about that,” Winnicker said. “He respects the members, but he doesn’t go along to get along. He does what he believes are in the city’s interests first, not politics.”